The present invention relates to a slot mechanism for a portable device (an electronic key) used in a vehicle such as an automobile, and to a smart ignition system. Specifically, the present invention relates to a slot mechanism that has a shutter for closing a slot when no object is inserted in the slot, and to a smart ignition system that has such a slot mechanism.
In recent years, engine start permitting mechanisms having a smart ignition function have been known in the art (for example, Japanese Laid-Open Patent Publication No. 2002-295089). Such an engine start permitting mechanism allows a user, who carries a portable device, to start the engine of a car by manipulating a switch on the car. This engine start permitting mechanism relieves the user of the chore of inserting a mechanical key portion of the portable device into the key cylinder.
An engine start permitting mechanism includes a portable device and a communication controller installed in a vehicle. The communication controller establishes mutual communication with the portable device, and checks an ID code transmitted from the portable device against an ID code of its own. When the ID codes match, the communication controller permits the engine to be started. The portable device has a battery as a power source enabling the mutual communication. When the battery is exhausted, the portable device is unable to transmit the ID code, and the communication controller is unable to permit the engine to be started. In such a case, the portable device is inserted into a slot provided in a instrument panel. Then, the communication controller transmits transponder driving radio waves to drive a transponder incorporated in the portable device, which generates a magnetic field in the slot. The magnetic field generates electromotive force at an immobilizer antenna of the transponder. The electromotive force activates the transponder, which, in turn, sends its own ID code to the communication controller. This enables the user to start the engine even if the battery of the portable device is exhausted. The slot mechanism of Japanese Laid-Open Patent Publication No. 2002-295089 has a shutter for closing the slot. The shutter is rotatably supported by a case.